Licensed Electrical Contractor Licensed Electrical Contractor Load Calculation and Services Questions and Answers 3

Question 1

When sizing service entrance conductors for a dwelling, what is the minimum ampacity requirement for 200-amp service using copper THWN conductors?

Accepted Answer

200 amperes

Answer

Service entrance conductors must have an ampacity of not less than the rating of the service, which is 200 amperes for a 200-amp service.

Question 2

What continuous load multiplier must be applied when calculating branch circuit and feeder conductor sizing?

Accepted Answer

125%

Answer

NEC 210.20(A) requires conductors for continuous loads to be sized at 125% of the continuous load.

Question 3

For an optional method dwelling unit calculation per NEC 220.82, what is the base load applied to the first 10 kVA of total connected load?

Accepted Answer

100%

Answer

Under the optional method in NEC 220.82, the first 10 kVA of general loads is taken at 100%.

Question 4

When calculating kitchen equipment load for a commercial occupancy with 6 pieces of equipment, what demand factor applies per NEC Table 220.56?

Accepted Answer

65%

Answer

NEC Table 220.56 specifies a 65% demand factor for six or more pieces of commercial kitchen equipment.

Question 5

What is the minimum grounding electrode conductor size required for a 200-amp copper service per NEC Table 250.66?

Accepted Answer

4 AWG copper

Answer

NEC Table 250.66 requires a minimum 4 AWG copper grounding electrode conductor for service entrance conductors up to 2/0 AWG.

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